Mounting structure of liquid sensor and liquid container

Abstract

A mounting structure of a liquid sensor comprising: a vibration cavity forming base portion which has a first surface and a second surface opposed to each other and in which a cavity for receiving a medium as a detection target is formed to be open toward the first surface side and a bottom surface of the cavity can vibrate; a sensor including a piezoelectric element having a first electrode formed on the second surface side of the vibration cavity forming base portion, a piezoelectric layer formed on the first electrode, and a second electrode formed on the piezoelectric layer; a mounting target member which is mounted with the sensor, the mounting target member having an upstream space which communicates with the cavity through an upstream flow path and a downstream space which communicates with the cavity through a downstream flow path; and an elastic seal member which is disposed between the sensor and the mounting target member and which seals a space between the sensor and the mounting target member.

1. A mounting structure of a liquid sensor comprising:
 a vibration cavity forming base portion which has a first surface and a second surface opposed to each other and in which a cavity for receiving a medium as a detection target is formed to be open toward the first surface side and a bottom surface of the cavity can vibrate; 
 a sensor including a piezoelectric element having a first electrode formed on the second surface side of the vibration cavity forming base portion, a piezoelectric layer formed on the first electrode, and a second electrode formed on the piezoelectric layer; 
 a mounting target member which is mounted with the sensor, the mounting target member having an upstream space which communicates with the cavity through an upstream flow path and a downstream space which communicates with the cavity through a downstream flow path; and 
 an elastic seal member which is disposed between the sensor and the mounting target member and which seals a space between the sensor and the mounting target member, 
 wherein the sensor further includes, on the first surface side, a flow path forming base portion which is stacked on the vibration cavity forming base portion and in which a liquid supply path for supplying liquid as the detection target to the cavity and a liquid discharge path for discharging liquid as the detection target from the cavity are formed, and 
 wherein the elastic seal member, in which a supply-side opening allowing the liquid supply path and the upstream space to communicate with each other and a discharge-side opening allowing the liquid discharge path and the downstream space to communicate with each other are formed, seals a space between the liquid supply path and the upstream space and a space between the liquid discharge path and the downstream space, respectively. 
 
   
   
     2. The mounting structure according to  claim 1 ,
 wherein an opening of the supply-side opening is larger than an opening of the liquid supply path and an opening of the discharge-side opening is larger than an opening of the liquid discharge path. 
 
   
   
     3. The mounting structure according to  claim 2 ,
 wherein an opening diameter of the supply-side opening is set two or more times greater than an opening diameter of the liquid supply path and an opening diameter of the discharge-side opening is set two or more times greater than an opening diameter of the liquid discharge path. 
 
   
   
     4. The mounting structure according to  claim 2 ,
 wherein the supply-side opening and the liquid supply path are disposed concentrically and the discharge-side opening and the liquid discharge path are disposed concentrically. 
 
   
   
     5. The mounting structure according to  claim 1 ,
 wherein openings of the liquid supply path and the liquid discharge path are set to the same size and openings of the supply-side opening and the discharge-side opening are set to the same size. 
 
   
   
     6. The mounting structure according to  claim 5 ,
 wherein the liquid supply path and supply-side opening and the liquid discharge path and discharge-side opening are symmetrical about the center of the cavity. 
 
   
   
     7. The mounting structure according to  claim 1 , further comprising a bias member that fixes the sensor to the mounting target member by biasing the sensor toward the mounting target member. 
   
   
     8. The mounting structure according to  claim 1 , further comprising a holding member which is mounted on the outer circumference of the elastic seal member to hold the elastic seal member externally. 
   
   
     9. The mounting structure according to  claim 1 ,
 wherein the mounting target member is a buffer member which has, as the upstream space, a supply-side buffer chamber communicating with the liquid supply path and, as a downstream space, a discharge-side buffer chamber communicating with the liquid discharge path. 
 
   
   
     10. The mounting structure according to  claim 9 ,
 wherein the supply-side buffer chamber and the discharge-side buffer chamber are symmetrical about the center of the cavity. 
 
   
   
     11. The mounting structure of a liquid sensor according to  claim 9 ,
 wherein the supply-side buffer chamber and the discharge-side buffer chamber have a volume ten or more times greater than a volume of the cavity. 
 
   
   
     12. The mounting structure according to  claim 9 ,
 wherein the buffer member is mounted on a container body having a liquid delivery opening for sending out liquid reserved therein, the supply-side buffer chamber communicates with a liquid reservoir chamber for reserving liquid, and the discharge-side buffer chamber communicates a liquid delivery space communicating with the liquid delivery opening for sending out the liquid reserved in the inner space of the container body. 
 
   
   
     13. A liquid container comprising:
 a container body having a liquid delivery opening for sending out liquid reserved therein; and 
 mounting structure according to  claim 1 , 
 wherein the mounting target member serves as a part of the container body, and the liquid delivery opening is communicated with the downstream space. 
 
   
   
     14. The liquid container according to  claim 13 ,
 wherein the sensor further includes a flow path forming base portion which is stacked on the first surface side of the vibration cavity forming base portion and in which a liquid supply path for supplying liquid as a detection target to the cavity and a liquid discharge path for discharging the liquid as the detection target from the cavity are formed, and 
 wherein the elastic seal member, in which a supply-side opening allowing the liquid supply path and the upstream space to communicate with each other and a discharge-side opening allowing the liquid discharge path and the downstream space to communicate with each other are formed, seals a space between the liquid supply path and the upstream space and a space between the liquid discharge path and the downstream space, respectively. 
 
   
   
     15. The liquid container according to  claim 13 ,
 wherein the elastic seal member is disposed in a portion other than a flow path wall of a flow path space in which the cavity, the upstream flow path, and the downstream flow path communicate with each other. 
 
   
   
     16. A mounting structure of a liquid sensor comprising:
 a vibration cavity forming base portion which has a first surface and a second surface opposed to each other and in which a cavity for receiving a medium as a detection target is formed to be open toward the first surface side and a bottom surface of the cavity can vibrate; 
 a sensor including a piezoelectric element having a first electrode formed on the second surface side of the vibration cavity forming base portion, a piezoelectric layer formed on the first electrode, and a second electrode formed on the piezoelectric layer; 
 a mounting target member which is mounted with the sensor, the mounting target member having an upstream space which communicates with the cavity through an upstream flow path and a downstream space which communicates with the cavity through a downstream flow path; and 
 an elastic seal member which is disposed between the sensor and the mounting target member and which seals a space between the sensor and the mounting target member, 
 wherein the elastic seal member is disposed in a portion other than a flow path wall of a flow path space in which the cavity, the upstream flow path, and the downstream flow path communicate with each other, and 
 wherein a flow path projection in which the upstream flow path and the downstream flow path are opened is formed to be projected from the mounting target member and the elastic seal member seals the space between the sensor and the mounting target member at the outer circumference of the flow path projection. 
 
   
   
     17. The mounting structure according to  claim 16 ,
 wherein a ring-shaped projection surrounding a periphery of openings of the upstream flow path and the downstream flow path is formed on a surface of the flow path projection opposed to the sensor. 
 
   
   
     18. The mounting structure according to  claim 16 ,
 wherein the upstream flow path and the downstream flow path are symmetrical about the center of the cavity. 
 
   
   
     19. The mounting structure according to  claim 16 ,
 wherein the upstream flow path and the downstream flow path have a flow path area smaller than that of the cavity and are set to have such a length that fluidal mass exists therein. 
 
   
   
     20. The mounting structure according to  claim 16 , further comprising a bias member that fixes the sensor to the mounting target member by biasing the sensor toward the mounting target member. 
   
   
     21. The mounting structure according to  claim 16 ,
 wherein the mounting target member is a buffer member which has, as an upstream space, a supply-side buffer chamber communicating with the cavity through the upstream flow path and, as a downstream space, a discharge-side buffer chamber communicating with the cavity through the downstream flow path. 
 
   
   
     22. The mounting structure according to  claim 21 ,
 wherein the supply-side buffer chamber and the discharge-side buffer chamber are symmetrical about the center of the cavity. 
 
   
   
     23. The mounting structure according to  claim 21 ,
 wherein the supply-side buffer chamber and the discharge-side buffer chamber have a volume ten or more times greater than a volume of the cavity. 
 
   
   
     24. The mounting structure according to  claim 21 ,
 wherein the buffer member is mounted on a container body having a liquid delivery opening for sending out liquid reserved therein, the supply-side buffer chamber communicates with a liquid reservoir chamber for reserving liquid, and the discharge-side buffer chamber communicates a liquid delivery space communicating with the liquid delivery opening for sending out the liquid reserved in the inner space of the container body. 
 
   
   
     25. A liquid container comprising:
 a container body having a liquid delivery opening for sending out liquid reserved therein; and 
 the mounting structure according to  claim 16 , 
 wherein the mounting target member serves as a part of the container body, and the liquid delivery opening is communicated with the downstream space. 
 
   
   
     26. The liquid container according to  claim 25 ,
 wherein the sensor further includes a flow path forming base portion which is stacked on the first surface side of the vibration cavity forming base portion and in which a liquid supply path for supplying liquid as a detection target to the cavity and a liquid discharge path for discharging the liquid as the detection target from the cavity are formed, and 
 wherein the elastic seal member, in which a supply-side opening allowing the liquid supply path and the upstream space to communicate with each other and a discharge-side opening allowing the liquid discharge path and the downstream space to communicate with each other are formed, seals a space between the liquid supply path and the upstream space and a space between the liquid discharge path and the downstream space, respectively. 
 
   
   
     27. The liquid container according to  claim 25 ,
 wherein the elastic seal member is disposed in a portion other than a flow path wall of a flow path space in which the cavity, the upstream flow path, and the downstream flow path communicate with each other.